In some cities, it's more dangerous to breathe than to smoke cigarettes.
I can imagine it's more dangerous to live and breathe in a certain city for a year than to smoke one cigarette a year (at some completely unpolluted location). But I have trouble imagining that it's more dangerous to live and breathe in any city than to smoke cigarettes non-stop, continuously for every second of the day (again at some completely unpolluted location).
So I suspect this somewhat-vague claim by The Economist has some truth, but we need to be more specific about the rate at which we're smoking cigarettes (and possibly other factors as well). And so my question:
In what sense (if any) is this claim true?